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A mixture of oil and water which is stable and cannot be separated by the gravity settling alone. Separation requires the factors other than gravity. Emulsions are formed by two immiscible liquids, emulsifying agent which is used as a stabilizer and agitation for converting from discontinuous phase to continuous phase<ref name=":0"><nowiki>https://www.aocs.org/stay-informed/inform-magazine/featured-articles/emulsions-making-oil-and-water-mix-april-2014?SSO=True</nowiki></ref>. Nature, amount of emulsifying agent and degree of agitation determine the stability of the emulsions. Unstable emulsions can be separated into water and oil in matter of time. Without treating, stable emulsions can take longer time to gets separated into water and oil. Emulsifier forms a physical layer around the compound by not allowing the droplets to coalesce<ref name=":0" />. They contain both hydrophilic (water loving or polar) and hydrophobic (oil loving or non-polar)<ref name=":0" />. Hence, they are attracted to both the polar and non-polar compounds. By their attractive nature they lower the interfacial tension between water and oil which prevents from stabilization of droplets and preventing emulsion from coalescence
A mixture of oil and water which is stable and cannot be separated by the gravity settling alone. Separation requires the factors other than gravity. Emulsions are formed by two immiscible liquids, emulsifying agent which is used as a stabilizer and agitation for converting from discontinuous phase to continuous phase<ref name=":0"><nowiki>https://www.aocs.org/stay-informed/inform-magazine/featured-articles/emulsions-making-oil-and-water-mix-april-2014?SSO=True</nowiki> (accessed 15 November 2021)</ref>. Nature, amount of emulsifying agent and degree of agitation determine the stability of the emulsions. Unstable emulsions can be separated into water and oil in matter of time. Without treating, stable emulsions can take longer time to gets separated into water and oil. Emulsifier forms a physical layer around the compound by not allowing the droplets to coalesce<ref name=":0" />. They contain both hydrophilic (water loving or polar) and hydrophobic (oil loving or non-polar)<ref name=":0" />. Hence, they are attracted to both the polar and non-polar compounds. By their attractive nature they lower the interfacial tension between water and oil which prevents from stabilization of droplets and preventing emulsion from coalescence


==Separating Emulsion==
==Separating Emulsion==
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#Applying microwave radiation to break the emulsion
#Applying microwave radiation to break the emulsion


Emulsifier’s function is to stabilize the system at sufficient time. It reduces the inter-facial tension between the layers of the compounds and decreases the rate of coalescence while coalescence happens when the two compound collide<ref name=":2">https://fqechemicals.com/forming-and-destabilizing-emulsions/</ref><ref name=":0" />.
Emulsifier’s function is to stabilize the system at sufficient time. It reduces the inter-facial tension between the layers of the compounds and decreases the rate of coalescence while coalescence happens when the two compound collide<ref name=":2">https://fqechemicals.com/forming-and-destabilizing-emulsions/ (accessed 15 November 2021)</ref><ref name=":0" />.


Destabilization of the mixture is the main purpose of the separation by making the mixture unstable and separating oil and water<ref name=":2" />. In oil industry at the well site the most common type of emulsion was oil in water whereas, at the refineries it was water in oil type emulsions. Methods such as adding demulsifies, Adjustment of pH, filtration, membrane separation and heating treatment are basically used for making the mixture unstable and separating<ref name=":2" />. Separation is the primary consist of process of coalescence. Equal partitioning of oil and aqueous phase gives the best results for in destabilization. Destabilization of the emulsion depends on few factors which are physical nature of the surfactants, existence of the electric or the static barrier, viscosity of the continuous phase, distribution size of the droplets, phase volume ratio and temperature<ref name=":2" />.
Destabilization of the mixture is the main purpose of the separation by making the mixture unstable and separating oil and water<ref name=":2" />. In oil industry at the well site the most common type of emulsion was oil in water whereas, at the refineries it was water in oil type emulsions. Methods such as adding demulsifies, Adjustment of pH, filtration, membrane separation and heating treatment are basically used for making the mixture unstable and separating<ref name=":2" />. Separation is the primary consist of process of coalescence. Equal partitioning of oil and aqueous phase gives the best results for in destabilization. Destabilization of the emulsion depends on few factors which are physical nature of the surfactants, existence of the electric or the static barrier, viscosity of the continuous phase, distribution size of the droplets, phase volume ratio and temperature<ref name=":2" />.
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==='''Agitation'''===
==='''Agitation'''===
Fluid is agitated in the first stage at the diverter plate at the inlet of the separator<ref name=":3">https://kimray.com/training/6-ways-separate-oil-and-water-emulsionwater-emulsion</ref>. The first process of the separation starts when the fluid hits the diverter plate. Resulting to this the change in the direction and change in velocity helps to break the surface tension and separation happens<ref name=":3" />. Agitation increase separation by not supporting for larger compounds to form as emulsion and helps the water to settle<ref name=":3" />.  
Fluid is agitated in the first stage at the diverter plate at the inlet of the separator<ref name=":3">https://kimray.com/training/6-ways-separate-oil-and-water-emulsionwater-emulsion (accessed 15 November 2021)</ref>. The first process of the separation starts when the fluid hits the diverter plate. Resulting to this the change in the direction and change in velocity helps to break the surface tension and separation happens<ref name=":3" />. Agitation increase separation by not supporting for larger compounds to form as emulsion and helps the water to settle<ref name=":3" />.  


==='''Flocculation'''===
==='''Flocculation'''===
Flocculation happens naturally during the formation of sedimentation process<ref name=":4">https://www.mt.com/ca/en/home/applications/L1_AutoChem_Applications/L2_ParticleProcessing/Formulation_Flocculation.html#overviewaf</ref>. Mixing is required for the flocculation. It is the process of providing a connection between its compounds. If the compound reaches together for forming as one compound, it creates Vander Waals forces to decrease the energy barrier between them<ref name=":4" />. Sedimentation is normally occurring with better weight, size and strength.
Flocculation happens naturally during the formation of sedimentation process<ref name=":4">https://www.mt.com/ca/en/home/applications/L1_AutoChem_Applications/L2_ParticleProcessing/Formulation_Flocculation.html#overviewaf (accessed 15 November 2021)</ref>. Mixing is required for the flocculation. It is the process of providing a connection between its compounds. If the compound reaches together for forming as one compound, it creates Vander Waals forces to decrease the energy barrier between them<ref name=":4" />. Sedimentation is normally occurring with better weight, size and strength.


===Coalescence===
===Coalescence===
Line 39: Line 39:
Separating two immiscible liquids (emulsion) can have a variety of applications:
Separating two immiscible liquids (emulsion) can have a variety of applications:


# One major application of separating emulsion is for breaking oil and water emulsions in oil wells.
#One major application of separating emulsion is for breaking oil and water emulsions in oil wells.
# The extraction of metals (froth floatation)<ref name=":5">https://www.doubtnut.com/question-answer-chemistry/what-are-emulsion-how-are-they-classified-describe-the-applications-of-emulsions-113073068</ref>
#The extraction of metals (froth floatation)<ref name=":5">https://www.doubtnut.com/question-answer-chemistry/what-are-emulsion-how-are-they-classified-describe-the-applications-of-emulsions-113073068 (accessed 15 November 2021)</ref>
# The preparation of lotions, creams, ointments in pharmaceutical and cosmetics<ref name=":5" />
#The preparation of lotions, creams, ointments in pharmaceutical and cosmetics<ref name=":5" />


==References==
==References==
<references />
<references />

Revision as of 06:54, 23 November 2021

A mixture of oil and water which is stable and cannot be separated by the gravity settling alone. Separation requires the factors other than gravity. Emulsions are formed by two immiscible liquids, emulsifying agent which is used as a stabilizer and agitation for converting from discontinuous phase to continuous phase[1]. Nature, amount of emulsifying agent and degree of agitation determine the stability of the emulsions. Unstable emulsions can be separated into water and oil in matter of time. Without treating, stable emulsions can take longer time to gets separated into water and oil. Emulsifier forms a physical layer around the compound by not allowing the droplets to coalesce[1]. They contain both hydrophilic (water loving or polar) and hydrophobic (oil loving or non-polar)[1]. Hence, they are attracted to both the polar and non-polar compounds. By their attractive nature they lower the interfacial tension between water and oil which prevents from stabilization of droplets and preventing emulsion from coalescence

Separating Emulsion

When one liquid is dispersed in a continuous liquid phase of a different composition an emulsion is formed[2]. The type of emulsions formed depends on the kind of liquid which forms the the continuous phase and thus we have: (1) Oil-in-water (O/W) when oil is dispersed in water(Oil suspended in aqueous layer)[2]; (2) water-in-oil (W/O) when water is dispersed in oil (water suspended in oil)[2]. Emulsions in oil industry are normally represented as "water-in-oil" or "oil-in-water" based on their volume of liquids ratios.

Basic steps involved in Separating Emulsion

Destabilization

Counteracting the stabilizing effect of the emulsifier destabilizes an emulsion. To increase the probability of coalescence of dispersed water droplets on contact, the tough skin or film surrounding the dispersed water droplets must be weakened and broken[2]. The following methods can be applied

  1. Adding heat to the emulsion
  2. Adding active chemicals compounds that are designed to the break the emulsion
  3. Applying electrical fields that promote coalescence
  4. Applying microwave radiation to break the emulsion

Emulsifier’s function is to stabilize the system at sufficient time. It reduces the inter-facial tension between the layers of the compounds and decreases the rate of coalescence while coalescence happens when the two compound collide[3][1].

Destabilization of the mixture is the main purpose of the separation by making the mixture unstable and separating oil and water[3]. In oil industry at the well site the most common type of emulsion was oil in water whereas, at the refineries it was water in oil type emulsions. Methods such as adding demulsifies, Adjustment of pH, filtration, membrane separation and heating treatment are basically used for making the mixture unstable and separating[3]. Separation is the primary consist of process of coalescence. Equal partitioning of oil and aqueous phase gives the best results for in destabilization. Destabilization of the emulsion depends on few factors which are physical nature of the surfactants, existence of the electric or the static barrier, viscosity of the continuous phase, distribution size of the droplets, phase volume ratio and temperature[3].

Acidification

It is one of the destabilization processes. It is effective in the W/O emulsion separation. The acid is sent to the oil and water interface so that the solid materials get absorbed at the interface which reduces the surface tension. Later the demulsifying agent replaces the emulsifying agent and makes the compound unstable, and separation can be done[3].

Agitation

Fluid is agitated in the first stage at the diverter plate at the inlet of the separator[4]. The first process of the separation starts when the fluid hits the diverter plate. Resulting to this the change in the direction and change in velocity helps to break the surface tension and separation happens[4]. Agitation increase separation by not supporting for larger compounds to form as emulsion and helps the water to settle[4].

Flocculation

Flocculation happens naturally during the formation of sedimentation process[5]. Mixing is required for the flocculation. It is the process of providing a connection between its compounds. If the compound reaches together for forming as one compound, it creates Vander Waals forces to decrease the energy barrier between them[5]. Sedimentation is normally occurring with better weight, size and strength.

Coalescence

Coalescence is basically a group of droplets or compounds forming to be a larger droplet when gets collided to each other[3]. Basically, separation process depends on the process of coalescence. There are two basic phenomena includes in the process of coalescence. Film drainage and film rupture. Aggregation of the droplets occur when they stay close to each other for longer times. Pressure and flow of the liquid are the two factor that affect film drainage[3]. If the interfacial tension on the layer between two compounds decreases, then the film gets rupture and the pressure difference between the compounds helps to form as a larger droplet[3]. So basically, the separation of the droplets also depend on the properties of the interfacial film and the coalescence depends on the film drain rates[3].

Gravity separation

Gravity separation is the most common method used in the oil industries. It depends on the differences in the densities of oil and water in emulsion[4]. Density differences allows water to settle down as water having higher density than oil. Being in non turbulent state, the specific gravity between them helps for the separation[4].

Retention time

It is the time for the fluid for staying in immovable state without any agitation inside a separator[4]. More separation happens with longer retention times. Separation is a time taking process. Reducing the velocity of the fluid helps for the separation by the gravity as the fluid have some time for the settling by gravity[4]. Retention times can be increased by having larger diameter separators as they allow more water to settle by gravity

Application of Separating Emulsion

Separating two immiscible liquids (emulsion) can have a variety of applications:

  1. One major application of separating emulsion is for breaking oil and water emulsions in oil wells.
  2. The extraction of metals (froth floatation)[6]
  3. The preparation of lotions, creams, ointments in pharmaceutical and cosmetics[6]

References

  1. 1.0 1.1 1.2 1.3 https://www.aocs.org/stay-informed/inform-magazine/featured-articles/emulsions-making-oil-and-water-mix-april-2014?SSO=True (accessed 15 November 2021)
  2. 2.0 2.1 2.2 2.3 N. Saifuddin and K.H. Chua , 2006. Treatment of Oily Waste Water Emulsions from Metallurgical Industries Using Microwave Irradiation. Biotechnology, 5: 308-314.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 https://fqechemicals.com/forming-and-destabilizing-emulsions/ (accessed 15 November 2021)
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 https://kimray.com/training/6-ways-separate-oil-and-water-emulsionwater-emulsion (accessed 15 November 2021)
  5. 5.0 5.1 https://www.mt.com/ca/en/home/applications/L1_AutoChem_Applications/L2_ParticleProcessing/Formulation_Flocculation.html#overviewaf (accessed 15 November 2021)
  6. 6.0 6.1 https://www.doubtnut.com/question-answer-chemistry/what-are-emulsion-how-are-they-classified-describe-the-applications-of-emulsions-113073068 (accessed 15 November 2021)